Since the majority of searches now happen on mobile devices, Google uses “mobile-first indexing,” meaning it primarily evaluates the mobile version of your site for ranking purposes. A mobile-friendly site should have responsive design, readable text without zooming, and easily tappable buttons and links. Core Web Vitals are a set of specific Google metrics measuring real-world user experience: Largest Contentful Paint (loading speed), First Input Delay (interactivity), and Cumulative Layout Shift (visual stability). These can be checked using Google Search Console and are increasingly important for both rankings and user satisfaction.